The purpose of this review is to explain the function of LL-37 in the pathogenesis of chronic sinusitis. LL-37 is the only human cathelicidin identified so far. LL-37 is an integral part of the innate immune,the role of which in chronic sinusitis is attracting more and more s attention.
Cathelicidins ; metabolism ; Chronic Disease ; Humans ; Sinusitis ; immunology ; metabolism ; pathology

The objective of this study was to construct an improved thioredoxin fusion protein expression system, and express the cathelicidin-derived peptide, Lf-CATH2. The improved fusion vector Lf-CATH2-pET32α(-TS) was successfully constructed by firstly deleting the thrombin site and S tag from the pET-32α vector, then inserting the Lf-CATH2 plus a thrombin site instead. Afterwards, Lf-CATH2 was expressed in Escherichia coli as fusion protein. After the cleavage by thrombin, Lf-CATH2 was released and subsequently separated using affinity chromatography. The antimicrobial activity of purified Lf-CATH2 was also examined. The improved expression vector significantly increased enzyme cleavage efficiency by 37%, and Lf-CATH2 could be expressed in high yield and maintain the biological activity. This novel thioredoxin fusion protein expression system enables a quick production of high-yield bioactive cationic peptides like cathelicidins.
Cathelicidins ; biosynthesis ; Chromatography, Affinity ; Escherichia coli ; Genetic Vectors ; Recombinant Fusion Proteins ; biosynthesis ; Thioredoxins ; genetics

OBJECTIVETo investigate the effect of antibacterial peptide LL-37 on the integrity of Acinetobacter baumannii biofilm.

METHODSA model of Acinetobacter baumannii biofilm in vitro was constructed by plates and crystal violet staining method, and the minimal inhibitory concentration of LL-37 was determined by broth dilution. The biofilm morphology was observed by scanning electron microscopy and biofilm formation was analyzed by the crystal violet staining of the adherent biofilm in the presence of antibacterial peptide LL-37.

RESULTSIn the Acinetobacter baumannii biofilm model, the minimal inhibitory concentration of LL-37 was 64 µg/ml; LL-37 caused structural damage of the biofilm at a low concentration of 2.5 µg/ml. The biofilm was decreased gradually as the concentration of LL-37 increased.

CONCLUSIONLL-37 even at a concentration far below its minimal inhibitory concentration can cause structural damage of Acinetobacter baumannii biofilm in vitro.

BACKGROUND AND OBJECTIVES: Salivary secretions and the secreted IgA in the secretions play a critical role in maintaining oral health via innate host defense mechanism. Cathelicidins are a family of peptides thought to provide an innate defensive barrier against a variety of potential microbial pathogens. LL-37, an antimicrobial peptide, is the only Cathelicidin protein so far identified in humans. The purpose of this study was to examine the expression of Cathelicidin in human salivary glands and to investigate upregulation of Cathelicidin in inflammatory conditions. MATERIALS AND METHOD: Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical staining were performed on 20 salivary gland tissues, of which 10 were normal and 10 were chronic sialadenitis. RESULTS: Cathelicidin mRNA transcripts were detected in the normal salivary glands and chronic sialadenitis. The level of Cathelicidin mRNA in chronic sialadenitis was significantly increased compared with that in the normal salivary gland. Cathelicidin protein was expressed in the glandular epithelium of the normal salivary gland and chronic sialadenitis. CONCLUSION: The results indicate that Cathelicidin might play an important role in the innate host defense of human salivary glands.
Cathelicidins ; Epithelium ; Humans ; Immunoglobulin A ; Oral Health ; Peptides ; RNA, Messenger ; Salivary Glands ; Sialadenitis* ; Up-Regulation*

BACKGROUND AND OBJECTIVES: Antimicrobial peptides and proteins play an important role in innate host defense, and this may be particularly important at mucosal surfaces that form the initial barrier between the host and the external environment. Epithelial cells are the first line of defense mechanism against microorganisms, where antimicrobial peptides are the major participants. Cathelicidins are the precursors of potent antimicrobial peptides that have been identified in several mammalian species. Cathelin-related antimicrobial peptide (CRAMP) is one of the antimicrobial peptides and is the only member of cathelicidin family identified so far in mouse. The present study was undertaken to investigate the expression of CRAMP in the eustachian tube epithelium of mouse. MATERIALS AND METHOD: Tissue samples from the mouse eustachian tube were recovered from its pharyngeal, middle, and distal segments. CRAMP was localized by immunohistochemical staining and mRNA expression was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: By immunohistochemical study, CRAMP was detected in epithelial cells and submucosal glands of the eustachian tube, but not in the negative control. Using RT-PCR, CRAMP mRNA was detected in the eustachian tube epithelium. CONCLUSION: The expression and localization of CRAMP in the epithelial cells and submucosal glands of the eustachian tube of mouse were defined. We found that CRAMP is one of the antimicrobial peptides found in the eustachian tube epithelium of mouse, and that it participates in the innate immune system of the eustachian tube.
Animals ; Cathelicidins ; Epithelial Cells ; Epithelium* ; Eustachian Tube* ; Humans ; Immune System ; Mice* ; Muscle Cramp ; Peptides ; RNA, Messenger

Infection is one of the main causes of death in clinical patients, and multi-drug resistance leads to ineffective treatment with conventional antibiotics. Therefore, it is imperative to develop new anti-infective drugs. Antimicrobial peptides cathelicidins are cationic host defense peptides found in many organisms. It has been demonstrated by in vivo and in vitro studies that antimicrobial peptides cathelicidins not only show broad-spectrum antibacterial activity and high sensitivity to drug-resistant bacteria, but also have a good guiding effect on the immune response. This paper summarizes the reports of antimicrobial peptides cathelicidins in recent years, highlighting their research achievements in antibiosis, anti-inflammatory, chemotaxis regulation and phagocytosis, providing new ideas for the treatment of infection-related diseases.
Anti-Bacterial Agents ; Anti-Infective Agents ; Antimicrobial Cationic Peptides ; Bacteria ; Cathelicidins ; Humans

BACKGROUND: A stem cell is an undifferentiated cell that has the potential for self-renewal and differentiation. Adipose-derived stem cells (ADSCs) have advantages in accessibility and abundance compared to other kinds of stem cells and produce many growth factors and hormones. OBJECTIVE: We investigated whether ADSC cultured media could be used as a therapy for atopic dermatitis. METHODS: ADSC cultured media was topically applied twice daily for 5 days to oxazolone-treated atopic dermatitis-like hairless mice. RESULTS: Topical application of ADSC cultured media improved the epidermal permeability barrier and keratinocyte differentiation, and restored the predominant Th2 phenotype when compared to vehicle. ADSC cultured media-treated epidermis also showed an increase in the expression of antimicrobial peptides cathelin-related antimicrobial peptide, mouse beta-defensein 3. CONCLUSION: Topical ADSC cultured media could be useful in the treatment of atopic dermatitis.
Animals ; Cathelicidins ; Dermatitis, Atopic ; Epidermis ; Intercellular Signaling Peptides and Proteins ; Keratinocytes ; Mice ; Oxazolone ; Peptides ; Permeability ; Phenotype ; Stem Cells

Objective: To fabricate TiO₂ nanotube material functionalized by antimicrobial peptide LL-37, and to explore its effects on biological behaviors such as adhesion and migration of human keratinocytes (HaCaT) and its antibacterial properties. Methods: The TiO₂ nanotube array (NT) was constructed on the surface of polished titanium (PT) by anodization, and the antimicrobial peptide LL-37 was loaded on the surface of TiO₂ nanotube (LL-37/NT) by physical adsorption. Three samples were selected by simple random sampling in each group. Surface morphology, roughness, hydrophilicity and release characteristics of LL-37 of the samples were analyzed with a field emission scanning electron microscope, an atomic force microscope, a contact angle measuring device and a microplate absorbance reader. HaCaT cells were respectively cultured on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of cell was observed by field emission scanning electron microscope. The number of cell adhesion was observed by cellular immunofluorescence staining. Cell counting kit-8 (CCK-8) assay was used to detect cell proliferation. Wound scratch assay was used to observe the migration of HaCaT. The above experiments were used to evaluate the effect of each group on the biological behavior of HaCaT cells. To evaluate their antibacterial effects, Porphyromonas gingivalis (Pg) was respectively inoculated on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of bacteria was observed by field emission scanning electron microscope. Bacterial viability was determined by live/dead bacterial staining. Results: A uniform array of nanotubes could be seen on the surface of titanium samples in LL-37/NT group, and the top of the tube was covered with granular LL-37. Compared with PT group [the roughness was (2.30±0.18) nm, the contact angle was 71.8°±1.7°], the roughness [(20.40±3.10) and (19.10±4.11) nm] and hydrophilicity (the contact angles were 22.4°±3.1° and 25.3°±2.2°, respectively) of titanium samples increased in NT and LL-37/NT group (P<0.001). The results of in vitro release test showed that the release of antimicrobial peptide LL-37 was characterized by early sudden release (1-4 h) and long-term (1-7 d) slow release. With the immunofluorescence, more cell attachment was found on NT and LL-37/NT than that on PT at the first 0.5 and 2.0 h of culture (P<0.05). The results of CCK-8 showed that there was no significant difference in the proliferation of cells among groups at 1, 3 and 5 days after culture. Wound scratch assay showed that compared with PT and NT group, the cell moved fastest on the surface of titanium samples in LL-37/NT group at 24 h of culture [(96.4±4.9)%] (F=35.55, P<0.001). A monolayer cells could be formed and filled with the scratch in 24 h at LL-37/NT group. The results of bacterial test in vitro showed that compared with the PT group, the bacterial morphology in the NT and LL-37/NT groups was significantly wrinkled, and obvious bacterial rupture could be seen on the surface of titanium samples in LL-37/NT group. The results of bacteria staining showed that the green fluorescence intensity of titanium samples in LL-37/NT group was the lowest in all groups (F=66.54,P<0.001). Conclusions: LL-37/NT is beneficial to the adhesion and migration of HaCaT cells and has excellent antibacterial properties, this provides a new strategy for the optimal design of implant neck materials.
Humans ; Titanium/chemistry* ; Antimicrobial Peptides ; Cathelicidins ; Sincalide ; Anti-Bacterial Agents/pharmacology* ; Nanotubes/chemistry* ; Dental Materials ; Bacteria ; Keratinocytes ; Surface Properties

Antimicrobial peptides/proteins are ancient and naturallyoccurring antibiotics in innate immune responses in a variety of organisms. Additionally, these peptides have been recognized as important signaling molecules in regulation of both innate and adaptive immunity. During mycobacterial infection, antimicrobial peptides including cathelicidin, defensin, and hepcidin have antimicrobial activities against mycobacteria, making them promising candidates for future drug development. Additionally, antimicrobial peptides act as immunomodulators in infectious and inflammatory conditions. Multiple crucial functions of cathelicidins in antimycobacterial immune defense have been characterized not only in terms of direct killing of mycobacteria but also as innate immune regulators, i.e., in secretion of cytokines and chemokines, and mediating autophagy activation. Defensin families are also important during mycobacterial infection and contribute to antimycobacterial defense and inhibition of mycobacterial growth both in vitro and in vivo. Hepcidin, although its role in mycobacterial infection has not yet been characterized, exerts antimycobacterial effects in activated macrophages. The present review focuses on recent efforts to elucidate the roles of host defense peptides in innate immunity to mycobacteria.
Adaptive Immunity ; Anti-Bacterial Agents ; Antimicrobial Cationic Peptides ; Autophagy ; Cathelicidins ; Chemokines ; Cytokines ; Homicide ; Humans ; Immunity, Innate ; Immunologic Factors ; Macrophages ; Negotiating ; Peptides

Antimicrobial peptides/proteins are ancient and naturallyoccurring antibiotics in innate immune responses in a variety of organisms. Additionally, these peptides have been recognized as important signaling molecules in regulation of both innate and adaptive immunity. During mycobacterial infection, antimicrobial peptides including cathelicidin, defensin, and hepcidin have antimicrobial activities against mycobacteria, making them promising candidates for future drug development. Additionally, antimicrobial peptides act as immunomodulators in infectious and inflammatory conditions. Multiple crucial functions of cathelicidins in antimycobacterial immune defense have been characterized not only in terms of direct killing of mycobacteria but also as innate immune regulators, i.e., in secretion of cytokines and chemokines, and mediating autophagy activation. Defensin families are also important during mycobacterial infection and contribute to antimycobacterial defense and inhibition of mycobacterial growth both in vitro and in vivo. Hepcidin, although its role in mycobacterial infection has not yet been characterized, exerts antimycobacterial effects in activated macrophages. The present review focuses on recent efforts to elucidate the roles of host defense peptides in innate immunity to mycobacteria.
Adaptive Immunity ; Anti-Bacterial Agents ; Antimicrobial Cationic Peptides ; Autophagy ; Cathelicidins ; Chemokines ; Cytokines ; Homicide ; Humans ; Immunity, Innate ; Immunologic Factors ; Macrophages ; Negotiating ; Peptides